 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.dtree;

 import org.eclipse.core.internal.utils.Messages;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.osgi.util.NLS;

 /**
  * A <code>DeletedNode</code> represents a node that has been deleted in a
  * <code>DeltaDataTree</code>. It is a node that existed in the parent tree,
  * but no longer exists in the current delta tree. It has no children or data.
  */
 public class DeletedNode extends AbstractDataTreeNode {

     /**
      * Creates a new tree with the given name
      */
     DeletedNode(String localName) {
         super(localName, NO_CHILDREN);
     }

     /**
      * @see AbstractDataTreeNode#asBackwardDelta(DeltaDataTree, DeltaDataTree, IPath)
      */
     AbstractDataTreeNode asBackwardDelta(DeltaDataTree myTree, DeltaDataTree parentTree, IPath key) {
         if (parentTree.includes(key))
             return parentTree.copyCompleteSubtree(key);
         return this;
     }

     /**
      * Returns the child with the given local name
      */
     AbstractDataTreeNode childAt(String localName) {
         /* deleted nodes do not have children */
         throw new ObjectNotFoundException(NLS.bind(Messages.dtree_missingChild, localName));
     }

     /**
      * Returns the child with the given local name
      */
     AbstractDataTreeNode childAtOrNull(String localName) {
         /* deleted nodes do not have children */
         return null;
     }

     AbstractDataTreeNode compareWithParent(IPath key, DeltaDataTree parent, IComparator comparator) {
         /**
          * Just because there is a deleted node, it doesn't mean there must
          * be a corresponding node in the parent. Deleted nodes can live
          * in isolation.
          */
         if (parent.includes(key))
             return convertToRemovedComparisonNode(parent.copyCompleteSubtree(key), NodeComparison.K_REMOVED);
         // Node doesn't exist in either tree. Return an empty comparison.
 // Empty comparisons are omitted from the delta.
 return new DataTreeNode(key.lastSegment(), new NodeComparison(null, null, 0, 0));
     }

     /**
      * Creates and returns a new copy of the receiver. Makes a deep copy of
      * children, but a shallow copy of name and data.
      */
     AbstractDataTreeNode copy() {
         return new DeletedNode(name);
     }

     /**
      * Returns true if the receiver represents a deleted node, false otherwise.
      */
     boolean isDeleted() {
         return true;
     }

     /**
      * Simplifies the given node, and returns its replacement.
      */
     AbstractDataTreeNode simplifyWithParent(IPath key, DeltaDataTree parent, IComparator comparer) {
         if (parent.includes(key))
             return this;
         return new NoDataDeltaNode(name);
     }

     /**
      * Returns the number of children of the receiver
      */
     int size() {
         /* deleted nodes have no children */
         return 0;
     }

     /**
      * Return a unicode representation of the node. This method
      * is used for debugging purposes only (no NLS please)
      */
     public String toString() {
         return "a DeletedNode(" + this.getName() + ")"; //$NON-NLS-1$ //$NON-NLS-2$
 }

     /**
      * Returns a string describing the type of node.
      */
     int type() {
         return T_DELETED_NODE;
     }

     AbstractDataTreeNode childAtIgnoreCase(String localName) {
         /* deleted nodes do not have children */
         return null;
     }
 }

